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Prevalence and mechanisms of macrolide resistance in Streptococcus pyogenes in Santiago, Chile

E L Palavecino1, I Riedel, X Berrios

  • 1Laboratory Services and Department of Public Health, Universidad Catolica, Santiago, Chile.

Antimicrobial Agents and Chemotherapy
|December 20, 2000
PubMed

Insights

Macrolide resistance in Streptococcus pyogenes is a growing concern. A study in Chile found 7.2% resistance, with most isolates showing the M or MLSB phenotype, indicating genetic diversity.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Antimicrobial Resistance

Background:

  • Streptococcus pyogenes is a significant human pathogen.
  • Macrolide antibiotics are crucial for treating S. pyogenes infections.
  • Emergence of macrolide resistance threatens treatment efficacy.

Purpose of the Study:

  • To determine the prevalence of macrolide resistance in Streptococcus pyogenes.
  • To characterize the resistance phenotypes and genetic diversity of resistant isolates.

Main Methods:

  • Collection and analysis of 594 clinical S. pyogenes isolates from Santiago, Chile (1990-1998).
  • Phenotypic characterization of macrolide resistance (M and MLSB phenotypes).
  • Serotyping and pulsed-field gel electrophoresis (PFGE) for genetic diversity assessment.

Main Results:

  • Overall prevalence of macrolide-resistant S. pyogenes was 7.2% (32 out of 594 isolates).
  • The M resistance phenotype was predominant (87.5%), followed by the MLSB phenotype (12.5%).
  • Serotyping and PFGE revealed significant genetic diversity among the resistant isolates.

Conclusions:

  • Macrolide resistance in S. pyogenes is prevalent in Santiago, Chile.
  • The M phenotype is the dominant resistance mechanism observed.
  • Genetic diversity suggests multiple origins or evolution of resistance.

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